Developing cardiac rupture as initial sign of acute myocardial infarction.

Pathological data are given of 4 patients in whom the development of cardiac rupture was the initial sign of myocardial infarction. The term 'concealed cardiac rupture' is proposed for this condition. In each instance the clinical diagnosis was 'onset of infarction', whereas the necropsy suggested that the acute onset of symptoms was caused by the start of rupture. The arguments for classifying the cases as 'concealed rupture' are (1) the lack of correlation between histological and clinical dating of the infarct, (2) the observation that the tear may take considerable time before actual epicardial breakthrough occurs, and (3) the fact that a high percentage of infarcts may pass clinically unnoticed.